Driving mechanism for phonographs and the like



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M. H. BENNETT ET AL.

DRIVING MECHANISM FOR PHONOGRAPHS AND THE LIKE H W m u fi w Filed 00%.

Patented Dec. 6, 1927-.

" UNITED STATES PATENT OFFICE.

MORRIS H. BENNETT AND HENRY C. ROGHETTE, OF WATEBIBURY, CONNECTICUT, AS-

SIGNORS TO SGOVILL MANUFACTURING COMPANY, A CORPORATION OF 6017- NECTICUT.

DRIVING MECHANISM FOR PHONOGRAPHS AND THE LIKE.

Application filed October 21, 1922. Serial No. 595,970.

This invention relates to certain improvements in electric driving mechanism for phonographs and the like.

Nitli an electrical motor drive for phonographs and the like certain requirements are necessary or desirable. The driving mechanism must drive the turntable or other" record carrying support with a substantially constant speed under varying loads, that is, for instance, the difference in load, arising when the needle is at different points respecting the outer circumference of the record. The structure must be such that the mechanism, when running, is noiseless so that the tones produced by the record are not impaired by noise or hum due to voltage changes, or other causes. The mechanism should be capacitated to operate on either an alternating or a direct current circuit, and must have a motor speed adjustable within a limited range. Furthermore, the speed of the turntable or other record support must be substantially constant irrespective of sudden changes in the voltage of the current delivered to the motor. Furthermore, in the best constructions the drive should be such that it may be run on currents having widely difirent voltages.

It is the especial object of the invention to produce an improved electrical driving mechanism for 'phonographs and the like in which the. power element is an electric motor, which will take care of these requirements. It is a further objectof the invention toproduce a structure in which a current supply varying widely in voltage may be used without necessitating any changes in the motor or in the driving mechanism operated thereby.- It is also an object of the invention to produce a construction in which -va riations in the motor speed due-to voltage changes in the current are automatically taken care of, so that a constant speed is delivered to the turntable or other record. support and the motor is prevented from racing due to excessive voltage changes.

With these and other objects not specifically referred to in view, the invention cansists in certain novel parts, arrangements and combinations which will be described in detail in connection Withthe accomp y ng drawings and the novel features thereof pointed out in the claims hereunto annexed.

In the drawings- Figure 1 is a vertical sectional view partly broken away of the improved driving mechanism;

Figure 2 is a detail partly sectional view taken on line 2-2 of Fig. 1;

Figures 3 and 4 are detail partly sectional and partly broken away views showing different positions of the clutch mechanism employed for keeping constant the speed transmitted to the turntable or other support.

Referring now to these drawings-the driving'mechanism is in the best constructions enclosed in a substantially dust-proof casing indicated at 1. This casing is supported in any suitable manner, as by being suspended from the underside of the top board 3 of a phonograph cabinet, the casing being secured inany suitable manner as by screws 4, and washers 2 interposed between the top board and the upper side of the easin 1.

Tvlounted to rotate above the top board 3 is. a record support which in the particular construction illustrated, includes a fiat table 5 of the usual type having a depending socket 6 in which is fixedly secured a driving spindle 7, this spindle taking hearing at its other end in a plate S 'fast on the inside of the bottom 9 of the casing 1, before referred to. This spindle is provided with a worm gear 10 through which *it is driven by means of connections hereinafter referred to.

The'driving connections will include an electric motor. This motor in constructions embodying the invention in its best form is a series wound motor so that it Wlll be 11111- versal, that is, will run on either a direct current or analternating current without change so that the mechanism may be employed with circuits furnishing current of either kind without necessitating any changes in the mechanism. i

As frequently happens in a circuit of either kind, the voltage in the circuit-may vary, which variation would cause a change the speed of the motor and a consequent change in the speed of the mechanism operated from the motor. In accordance with the invention, means are provided whereby this change in speed is controlled so that the driving speed delivered to the driving spindle of the turntable is substantially constant under varying loads.

While this may be accomplished in various ways, in the preferred construction, and as shown, there are preferably employed two motor speed controlling devices, one of which acts directly on the motor itself and the other of which employs a governor-controlled clutch by which a Very fine control or adjustment of the motor speed is effected. In the particular construction illustrated for effecting this, and referring first to the control acting directly on the motor there is shown a motor having an armature 12 rotating between field pieces 13, 14, mounted in anv suitable manner in casing 1 as on bolts 15,. The armature 12 is mounted on a fixed armature shaft 16 by means of a sleeve indicated at 17 so that the armature may have a small longitudinal movementwith respect to the field, on this shaft. This sliding movement of the armature on the shaft is caused by the magnetic flux which, when the current is turned into the motor, causes a movement of the armature with respect to the field. The armature is, therefore, mounted on the axle so that normally the armature is positioned outside the plane of the maximum magnetic flux of the field, and the magnetic pull tends to slide the armature in the plane of the maximum flux.

This movement of the armature is 0011- -working conditions, the armature will be drawn against this stop and roughly braked, whereby the motor will .be pre-,

vented from overspeeding.

In the best constructions, furthermore, this stop will be adjustable so that the motor speed may be varied within certain limits. While this may be effected in various ways, in the construction illustrated where a clutch is employed for effecting a fine adjustment for the control of the motor speed, the arma ture shaft is provided with one member 18 of a cone clutch. This clutch is provided with a flange 19 adapted to engage with a suitable stop and brake member 20. The clutch member 18 is secured to revolve with the armature and is formed in the particular construction illustrated, with a hub 21 secured to the armature sleeve 17 by means of screws 23.

The brake member may be in the form of a block, the face of which may be covered if desired with an suitable braking material. 1 This brake b ock is secured on an arm 24 rising from a rock shaft 25 journaled' in bearings 26 in the bottom 9 of the casing 1 before referred to The braking block is,

' members.

sprmg governor comprising flat springs.

as before stated, in the best constructions adjustable with respect to the flange 19 with which it engages, so. that it may occupy a position .nearer or farther away from the flange so as to permit a greater or less moveeasily and conveniently effected by means of an adjusting screw 28 provided with a milled head 29, this adjusting screw working in a socket 30 provided in the top board 3 before referred to of the phonograph cabinet, and the rod is rocked against a spring 300 which holds the rod in adjusted position. 'With this construction a simple adjustment of the brake block may be provided.

In accordance with the invention means are provided for effecting a fine and accuratev speed control or adjustment from the motor to the turntable spindle. In the particular embodiment of the invention illustrated.

this includes a clutch comprising the clutch member 18 before referred to, having a recess 31 in its face with which co-operates a cone clutch member 32 having a leather face 33. This cone. is provided with a hub 34, provided with a sleeve 35 mounted on a short shaft 36 so that the cone can have a sliding movement on the shaft toward and from the recessed clutch member 18. Co-operating with this cone clutch is a governor for controlling the engagement of the clutch As shown this governor is a three of these springs being shown, marked 37, 38 and 39. These springs are secured at one end of the hub 34 before referred to and at their other ends are secured to a block 40 secured on the shaft 36 by set screw 40, the springs being secured to the hub and block in any suitable manner as by screws 41. These springs have secured thereto weights 42, one weight being secured to each spring. As the speedgocs up the weights 42 spread the springs apart and act to ull the clutch longitudinally of the shaft and causes a sli or disengagement between the cone 32 an the clutch member 18.

The short shaft 36 is provided at one end with a worm 43 which engages with the worm wheel 10 before referred to on the driving s indle 7 of the turntable 5 and acts to drlve the spindle at a constant speed. This shaft 36 may be supported many suitable manner. In the best constructions, however, the shaft is supported so that a slight adjustment between the worm and the vworm wheel may be provided to take up At its other end the shaft is supported in a plug having an eccentric recess 46. This plug extends through a hub 47 formed at the end of the casing 1 and is provided with a milled head 48 so that the plug'may be given a rotary movement in the hub. lhe plug 1 is kept from rotation by means of a set screw 49 passing down through a hollow tapped in the hub 47 before referred to.

Means will be provided for oiling the spindle and the armature shaft which may be of any suitable and desired character. In the best constructions, however, these means will be such as to be effective for long periods with but one oiling. in the particular construction illustrated, the end wall of the casing 1 through which the armsture shaft 16 passes. is provided with a recess in which is set a block of felt or other suitable oil-absorbing material 50, this block being held in place by a plate 51. Oil is supplied to this felt block by means of an oil port 52, preferably passing diagonally through a hub 53 formed on the end of the casing 1. With this construction suilicient oil is supplied to the shaft, the rotation of the shaft causing the oil to pass along the same, and to effect a suitable lubrication thereof.

The spindle '2 is or may he lubricated'in a similar manner. As shown there is provided a bloclr 54 suitably supported. as on shoulders 55, formed on the top wall of the casing 1, this block acting as an upper hearing for the driving spindle 7, before referred to. This block is provided with a recess 56 in which is set a felt block 57 to which oil is-supplied through an opening 58 surrounding the spindle 7. v

In machines embodying the invention in its best form means will be provided whereby the 'driving'mechanism and motor may be employed with circuits having power current of widely varying voltages. For instance, the motor and drive may be arranged for a circuit carrying 32 volts. it may be desirable to use the same machine on a circult carrying llO volts or a circuit carrying 220 volts. This is ed'ccted by providing a mounting for a fuse block arranged on a part of the casing where it is readlly accessible so that by removin and inserting suitable resistances the mec anism maybe employed with wide voltage variations such as referred to. In the particular construction illustrated, there is provided a pair of the usual fuse clips 60, 61, secured to the bottom of the casing bybinding posts 62 and 63.

As before stated, the motor is wound in 2. In a, driving mechanism for sistance 64, binding post 63 and out through wire 70.

The operation of the mechanism is believed to be clear from the foregoing, but far completeness the following may be adde It may be stated that the parts are set so that the mechanism will properly function at a motor speed of say 20% below the normal voltage that should be suplied .from the power source, the slip oi. the clutchtaking care of the difference from normal voltage. Theparts are also made ofsuflicient weight so that the momentum will take of any momentary drop in voltage be-. low the 20% minimum. W hen the machine is started the governor is relied on to determine the speedat which the table runs, the governor acting to keep this speed constant. operates the clutch and causes a slip hetween the clutch members when the motor goes overspeed so that the actual driving speed transmitted from the motor to the spindle remains substantially constant. llhe motor armature is run at a speed as great or greater than the governor, the step control- As the speed goes up the governor ling this speed to a certain extent. For an While the invention has been described in 1 what is believed to be its best embodiment,

it will he understood that various changes may he made in the construction shown and described without departing from the invention and that the invention as regards certain of its features is not to be restricted to a motor construction in which the armature has a slight movement relatively to its field.

What we claim is: l. lln a drivi-n mechanism for phonographs' and the h e, the combination of a record support, an electric motor, means for controlling any substantial fluctuation I in the motor s eed due to variations in volt age only, a c uteh driven from the motor,

a governor controlling theengagement of the clutch members, and connections from" the clutch for driving the record support.

- graphs and the like, the combination of a driven therefrom, a governor controllingthe engagement of the clutch members, and connections from the clutch for driving the record support.

Ina driving mechanism for phonographs and the like, the combination of a record support, an electric motor having a sliding armature normally outside the plane of the maximum magnetic flux of the field, a brake for the armature and co-operating therewith to control speed fluctuations due to variations in voltage only,,a clutch mechanism driven from the motor, a governor controlling the engagement of the clutch members, and connections from the clutch for driving the record support.

4. In a driving mechanism for phonographs and the like, the combination of a record support, mechanism for driving the support, an electric motor, means for effecting a control of fluctuations in the motor speed due to variations in voltage only, and separate means for effecting an accurate control of the support driving mechanism.

5. In a driving mechanism for phonographs and the like, the combination of a record support, mechanism for driving the support, an electric motor, means actuated by voltage changes for effecting a control of fluctuations in the motor speed due to variations in voltage only, and separate means for effecting an accurate control of the support driving mechanism.

6. In combination, adriving motor, a driven shaft, a clutch 'therebetween, means associated with the motor and controlled by variations in the voltage supply to control the resulting variations in motor speed, and means associated with the driven shaft to control the clutch connections upon variation of the speed of the driven shaft where by a uniform speed of motor and shaft is maintained.

7. In combination, a turntable, a motor for driving said turntable, late the speed of the motor in accordance with variations in voltage only, means to regulate the speed of the turntable, means to cause the turntable regulating means to regulate the speed of, the turntable independently of the motor regulating means, and means to cause the motor regulating means to regulate the speed of the turntable.

8. In combination, a driving shaft havin a motor armature mounted thereon, fiel coils disposed about said shaft, said armature being normally outside the maximum magnetic field created by said coils, means to permit said armature to slide longitudinally into and out of said maximum field in response to variations in voltage only, and means coacting therewith to control the speed of said motor, a driven shaft, a clutch connecting said driven shaft with said driving shaft, governor means on said driven shaft to control the enga ement of said clutch whereb the speed 0 said driven shaft may be furt er controlled.

In testimony whereof, we have hereunto set our hands.

MORRIS H. BENNETT. HENRY o. ROGHETTE.

means to regu- 

